Current messaging systems are partitioned into coverage zones for delivery of messages to subscriber units. In a one-way messaging system a subscriber unit is typically assigned to a "home" coverage zone, to which all messages for the subscriber unit are routed unless the user of the subscriber unit requests temporary coverage in a different coverage zone, e.g., when traveling. In a two-way messaging system, a subscriber unit can sense when it is leaving the home coverage zone and can request registration in a new zone being entered. Thus, the two-way system can keep track of the subscriber unit's location and can route messages automatically.
Future messaging systems will incorporate multiple communications capabilities that will require different transmission bandwidths. For example, a simple numeric or alphanumeric message will require less bandwidth than a lengthy information services message or a FAX message. In general, higher bandwidth will correspond to shorter transmission range. This fact will allow for the integration of a relatively low bandwidth, wide area backbone messaging service network, with one or more higher bandwidth networks downtown, for example, and very high bandwidth networks in-building. Because the higher bandwidth and very high bandwidth networks are decoupled from one another and from the relatively low bandwidth backbone network, extensive reuse will boost system capacity enormously.
If such future systems were to be set up conventionally, the very high bandwidth networks would be treated as additional zones within the higher bandwidth networks, which in turn would be treated as additional zones within the low bandwidth network. Background scanning or an equivalent technique would allow the subscriber unit to detect when higher bandwidth service is available. The messaging system would keep track of the subscriber unit's location through registration messages sent by the subscriber unit whenever it enters a new zone. Because some of the zones would have a very small size (office size or smaller), the number of registrations would explode. Getting a cup of coffee, for example, could result in dozens of registrations while passing by one's colleagues' cubicles. Such an explosion of registrations would be disastrous, as little air time would be left for normal, non-registration messages.
Thus, what is needed is a method and apparatus that will allow multiple communications capabilities requiring multiple bandwidths to be provided without causing an explosion of registration messages.